Bad stress, also called distress, is a response to a stimulus that negatively disrupts our physical/mental or emotional environment. A stressful event has multiple consequences for our physiology, the main being the “fight or flight” response. Epinephrine, more commonly known as adrenaline, is a hormone secreted from the adrenal glands, which are near the kidney in the human body. When people feel emotions such as fear (any type including freeze, faint, flee and fight) or anger, this causes adrenaline to be released into the bloodstream, which causes an increase in heart rate, muscle strength, blood pressure, and sugar metabolism. The “flight or fight response” prepares the body for strenuous activity. Adrenaline is found in tiny amounts in the body, in amounts that vary from individual to individual; it is essential for maintaining the heart because of its ability to divert blood to tissues under stress. Constant adrenaline production through ongoing or repeated stress, however, triggers a chronic stress response in the body leading to cortisol production, and an elevated level of cortisol in the body has been shown to lead to disease. Exposure to chronic stress induces various physical, emotional and mental results that can ultimately lead to disease. Stress-related disease is a global health problem that costs the US economy $190B each year. There is a great need in the art for recognizing, decreasing and minimizing bad stress.
Another aspect of stress is good stress. As used herein, eustress means beneficial stress—either psychological, physical (e.g., exercise) or biochemical/radiological (hormesis). The term was coined by endocrinologist Hans Selye, consisting of the Greek prefix eu-meaning “good” and stress, literally meaning “good stress.” Typically the stress referred to in this document is bad stress.
As is known in the art, the most optimal level of stress is a minimum of bad stress and an amount of eustress. There is a need in the art for optimizing the quantities and qualities of stress experienced, in a way that is customizable for each person.
For example of societal cost related to stress, 60-80% of primary care doctor visits are related to stress, yet only 3% of patients receive stress management help. Big and little stresses can cause similar metabolic cascades in the body. Little stresses are not irrelevant. When we feel stressed, we are reactive, and we don't have access to all our intelligence and brain capacity for making conscious choices. Instead we become defensive. People can also become numb to stress and not realize the impacts to them on their body and in their lives and work. The best ways to address stress and its impacts are to notice stress in the moment and take actions: to stop the increase of stress that is happening; to decrease the amount of stress experienced during regular repeated events; to decrease the quantity, duration and intensity of stressful events one experiences; and to learn ways to decrease one's stress baseline. This can be achieved by learning calming methods and by making different decisions to avoid stressful scenarios. There are needs in the art for noticing stress in the moment and providing real-time feedback about the amount of stress experienced above a previous state or a control comparison state.
Most stress occurs during everyday activities, hence stress needs to be measured throughout a person's normal routine. Some devices known in the art can measure stress in artificial settings, such as with lie detector tests and biofeedback machines. Such devices in real life applications need to be convenient and more accurate—as this yields higher efficacy.
People need to be alerted to stress when it occurs so changes can be implemented quickly to alter their physiological state immediately. This also allows gradual learning of new patterns and allows implementation of new enhanced responses, perhaps eventually with no reminder or alert system.
Recently there has been a great rise in the use of wearable devices. This began in the medical industry and then subsequently spread to the fitness industry. This interest has expanded to include many aspects of health. There has been a desire in the field to measure heart rhythms with wearable devices since people want direct feedback about their body as they go about life activities. New technology has allowed smaller, longer lasting devices that are practical for everyday use. Real-time monitoring and feedback is motivating—people are competing to better themselves and against others as motivation. The signals in extremities, such as the wrist, where wearables are often placed, are smaller and more subtle than on the trunk of the body nearer the heart, so the wearable device must be more sensitive. Wearables also need to be low power so that people can wear them for extended periods without recharging.
Relevant wearable devices known in the art include:                1) FITBIT TRACKER is advertised as using a three-dimensional accelerometer to sense user movement (steps taken, distance walked, calories burned, floors climbed and activity duration and intensity). It also is described as measuring sleep quality by tracking periods of restlessness, how long it takes the wearer to fall asleep and how long they are actually asleep.        2) SPIRE is described as using sensors with algorithms to sense activity and breathing patterns. These sensors are said to detect the respiratory movement when worn on a belt clip type apparatus by measuring expansion and contraction of abdominal and/or thoracic cavities. With the SPIRE MIND and BODY TRACKER and companion app on an iPhone, one supposedly can become more mindful and calm throughout the day. It clips to pants or a bra, and the tiny Spire Stone is said to sense respiratory patterns to detect changes in one's state of mind (Tense, Calm, and Focus). With gentle notifications, insights, and breathing exercises, Spire is said to unlock a more mindful, balanced, and productive day. One's state of mind affects how one breathes. But how one breathes can also change one's state of mind. For example, studies have uncovered how slow, deep and consistent breathing can lower blood pressure, reduce stress, and increase the flow of endorphins in the blood stream. Spire is said to notify via an app on the iPhone or iPad when the wearer is tense, needs to take a deep breath, has just experienced an extended streak of calm, and other functions.        3) PEBBLE device has a programmable CPU, memory, storage, Bluetooth, a vibrating motor, a magnetometer, an ambient light sensor, and an accelerometer working in concert to provide biofeedback data to the user.        4) GOOGLE WATCH prototype is said to continuously measure biometric data including pulse rate and skin temperature and to analyze fine motion, including gait and balance. The watch is described as also measuring ambient temperature, noise and light, as well as altitude, which help to provide context for the biometric data.        5) APPLE WATCH is described as equipped with heart rate measuring circuits, which uses infrared and visible-light LEDs and photodiodes.        6) MICROSOFT BAND, released in 2014 (and 2nd edition in 2015) is described as having the following features: GPS, Ambient light sensor, UV sensor, Skin temperature sensor, Capacitive sensor, Galvanic skin response sensor, and Barometer.        
Some wearables are now attempting to measure and address a user's emotional states.                7) The WELLBE bracelet is said to monitor a person's heart rate using a patent-pending algorithm to determine their stress and calmness levels based on time, location and people met throughout your day. Crafted from cork, the WellBe bracelet is advertised as lightweight, durable, and soft against skin.        8) FEEL.CO is shown to have four integrated sensors on a wristband and said to monitor a variety of physiological signals such as, electrodermal activity, blood volume pulse, and skin temperature, while proprietary algorithms in the background are said to translate those bio-signals into emotions.        9) ALTRUIS, designer wearable technology by VINAYA, is said to filter a person's smartphone notifications to improve their digital balance, so a person stays connected, not distracted. It is a jewelry-based activity tracker by London-based Vinaya that comes in a ring or necklace format.        10) The PIP is a small handheld wearable fitness device that is said to track stress through the skin and couple with game technology to encourage people to relax. It is not wearable in the typical way—one carries it and must pause from normal activity to put one's thumb(s)/finger(s) on it. Two games are available on the app—one in which the user helps turn a landscape from winter to summer and another where the user races a dragon against a peer (the less stressed person wins). A person's stored stress stats are said to be available too, but the focus of this product appears to be making stress relief fun. It is said to achieve this by detecting variations in electrodermal activity (EDA). The skin pores on fingertips are said to be extremely sensitive to changing levels of stress. Pip supposedly accurately captures these changes and, through biofeedback, allows a user to visualize them.        11) OLIVE is said to analyze patterns and biological indicators by continuously monitoring the complexity of a person's stress behind the scenes to help them build awareness of their body's stress response. Everyone's stress is different. Supposedly Olive gets to know how stress is triggered. This product is not yet in production.        12) NEUMITRA is said to have embedded proprietary biomodules help measure and manage the autonomic nervous system. The product is said to provide a real-time autonomic score, assessing physiology and its interaction with movement and temperature. The biomodules are said to be encased in a design that seamlessly blends into daily life, allowing a person to take advantage of understanding their brain health every minute of every day        13) The LIEF is an ultra-thin biosensing patch that is said to measure heart and breath. Lief is said to teach control over a person's natural stress response through gentle, safe biofeedback exercises. It is said to reduce triggered responses so one stays mindful and in control throughout the day.        14) ZENSORIUM is marketed as a wearable fitness monitor that differentiates good stress from bad stress, tracks activity with heart rate sensing, and provides advanced sleep science insights with REM/NREM. Zensorium Being is said to map mood into four different zones, differentiating good from bad stress. It is said to sense energy, heart rate and changes in blood pressure, and determine emotions from heart rate variability. Supposedly capable of continuous monitoring, it claims to know when a wearer is stressed and provides steps for deep breathing exercises to reduce stress. This same company also makes Tinke, a device attached to the iPhone that is said to monitor stress and blood oxygen saturation by measuring heart rate, respiratory rate, blood oxygen saturation and heart rate variability to determine fitness and stress indices.        15) JAWBONE is a world-leader in consumer technology and wearable devices, building hardware products and software platforms powered by data science. Jawbone's UP® system is said to help people live better by providing personalized insight into how they sleep, move and eat. The company's approach to lifestyle tracking may be relatively unique, with over 600 patents granted or pending related to its ecosystem and wearable technology manufacturing processes. Jawbone is also the creator of the best-selling JAMBOX® family of wireless speakers, the award-winning Jawbone ERA® Bluetooth® headsets, and NoiseAssassin® technology. Headquartered in San Francisco with offices globally. Their products are said to measure Heart rate, Respiration and Galvanic Skin Response (GSR) combined with a Tri-axis accelerometer. The Jawbone products typically use optics for measurements. Their best product appears to have 4 electrodes, is said to require the user to be still during measurements, and measurements can only be obtained about every hour, not continuously. It is said to measure heart rate upon waking and then passively at regular intervals through the day by measuring electrical properties in the skin. Their products also use a lot of power.        16) KARDIA was developed by AliveCor, Inc., a privately held company headquartered in San Francisco. They produce a band which they claim allows people to take control of their heart health through the use of innovative mobile health solutions including Kardia Mobile, Kardia Band, the AliveCor app and Kardia Basic and Premium heart care services. A wristband is supposedly used to provide an ECG to medical providers, for use for conditions such as Atrial Fibrillation, a common heart condition. It is unclear how many electrodes are used in their style device, often 4 or more. The technology appears basic and uses an optical sensor to provide information.        17) Two new upcoming products that are not yet on the market are the SENCEBAND and SENCEHUB, which are described on kickstarter. SenceBand is said to accurately measure ECG signals from one wrist. SenceHub is said to turn those raw ECG signals into emotional insights.        
SenceBand's ECG Tracking from One WristSenceBand is said to measure ECG using a patent-pending technology that allows it to cancel out the electromagnetic “noise” from the wearer's body. This mechanism is said to filter out things like electrical signals from muscle contractions and leave only the electromagnetic feed from the heart (ECG). This filtering method is said to allow SenceBand, a smart bracelet, to measure ECGs from one wrist. It claims that it is capable of detecting up to 64 emotions from placing the HRV into an algorithm contained within the ScenceHub software. The Sence wristband is transmitted to a CardioCloud service, also developed by Platform 20K, and is said to continuously monitor. This service is offered to any medical professional to analyze and store cardiovascular data from any internet-enabled cardiograph. It is unknown if Sence products are able to do what they claim nor what technology is used, as products are not yet on the market, and there is not much product documentation available.
The detailed hearth rhythms detectable by non-wearable ECG medical products have never before been detectable with wearable devices.
There are currently no wearable devices for sale on the market that are convenient for everyday life activities that accurately and continuously measure stress, with the accuracy of medical devices. Some devices known in the art for detecting stress attempt to do so by extracting HRV and pulse derived typically from ECG by plethysmography. Some products attempt to measure ECG using optics, which requires much more power. Attempting these methods requires larger and heavier equipment and/or so much power that devices are not practical for everyday activities, they can't measure continuously, therefore they are not as efficacious and need to be recharged frequently.